Oscillograph



Oct. 28, 193-0. 0. ACKERMANN OSCILLOGRAPH Filed June 22, 1929 OttoAcKer'mann ATTORNEY Patented. Oct. 28, 1930 UNITED STATES PATENT OFFICEom'o AOKmANN, OF WILKINSIBURG, PENNSYLVANIA, ASSIGNOR TO WESTINGH IOUSEELECTRIC & MANUFACTURING COMPANY, A CORPO RATION OF PENNSYITVANIAoscILLoeaArn Application filed June 22,

' a device of the above indicated character that shall comprise fewerparts than similar devices heretofore employed.

Another object of my invention is to provide a single or unitary deviceor means that shall perform the flmction of a plurality of elementsheretofore employed.

Another object of my invention is to provide an oscillo raph, of thecathode-beam type and embo ying a target and an apertured shield, thatshall provide greater deflection of the beam for a given space and thatshall permit both the target and the opening in the shield to be smallerthan in slmilar devices heretofore employed.

A further ob'ect of my invention is to provide an electrical apparatusthat shall be simple and durable in construction, economical tomanufacture and effective in its operation.

Heretofore, in cathode-beam oscillographs for deflecting the beam inaccordance with a quantity to be measured on a sensitized record chart,it has been usual to protect the chart from diffusion of the beam,during periods that the beam is not being deflected from its neutral orzero position, to interpose a beam-absorbing target and a shield havingan aperture in line with the beam in the neutral position thereof.

In order to direct the beam, aside from the'target, through the shieldopening, it has been usual to provide flux-producing means, such ascondenser plates for initially deflecting the beam, a secondflux-producing means for re-directin the deflected beam and a thirdflux-pro ucing means for concentrating the beam. A fourth flux-producingmeans is also usually provided to further deflect the beam in accordancewith a time constant.

In practicing my invention, I provide a single or unitary device, means,or entity which both concentrates and re-directs the beam, after it hasbeen initially deflected,

1929. Serial No. 373,042.

thereby replacing a plurality of devices or means, such as the secondand third means mentioned above, by a single entity and correspondinglysimplifying, by reducing the number of parts and the size of theapparatus and rendering it more effective.

Fig. 1, of the accompanying drawing, is a diagrammatic view of anoscillograph embodying my invention, together with a diagram. ofappurtenant circuits and apparatus for rendering it operative.

Fig. 2, is a top plan view of a diagrammatic structure shown in Fig. 3.

Fig. 3 is an enlarged view of a portion of the device shown in Fig. 1,with certain spaces represented as geometric solids, and

Fig. 4 is a diagrammatic representation of a space discharge or beam,illustrating how it difl'uses from a position near its origin andbecomes concentrated before reaching its objective.

Referring to Fig. 1, the device comprises, in general, a fluid-tightvessel or container having a lower-end or base chamber portion 2 for thereception of a record-receiving element 3, an intermediate orbeam-control chamber portion 4 and a top or electrode chamber 5, acathode 7, an anode 8, initial beam or trace-deflecting means, such ascondenser plates 10, a concentration coil 12, a target 14, a shield 15having an aperture 16 therein, further beam-control means, such ascondenser plates 18, a source 19 of electromotive force for energizingthe electrodes 7 and 8, a transmission line or other circuit 20, avoltage of which is to be measured, a voltage-reducing device 22 forenergizing the condenser plates 10 in proportion to the voltage betweenthe line 20 and the ground 23, a source 25 of electromotive force forthe concentration coil 12 and a circuit 27 for energizing the condenserplates 18.

The vessel, comprising the parts 2, 4, and 5, may be of any suitableconstruction that is sufliciently vacuum or gas tight; the parts 2 and 4being preferably of metal and the part 5 preferably of lass.

The lower-en or base chamber portion 2 may be variously constructed, asby having a door, not shown, for the reception of the record element 3,by having one of its walls of glass or other material whereby theelement 3 may receive its record through such wall, or be otherwiseconstructed to receive a stationary record plate, as shown, or a movableplate or roll, as is well known in the art.

The anode 8 is provided with an opening 29 throu h which a beam 30, inthe form of a permeabIe trace through space or an electrical dischargefrom the cathode 7, is normally projected along a line intercepting thetarget 14 and extending through the opening 16 in the shield 15.

The concentration coil 12, suitably spaced from and located beneath thecondenser plates 10, is preferably located outside the intermediatechamber portion 4, as illustrated, although it may be disposed withinthe chamber by reducing the size of the coil or by enlarging the size ofthe chamber at this position.

Upper and lower magnetic disks 32 and 33, respectivel are disposedsubstantially in the planes of the ends of the coil 12 and are providedwith slots 35 and 36, respectively, through which the beam 30 may pass.The coil 12 and the disks 32 and 33 are supported in the relations shownin any suitable manner, these elements, 12, 32, and 33 togetherconstituting the single means, unitar device or entity for performingthe double unction of concentrating and deflecting or redirecting thebeam 30, as will hereinafter more full appear.

The target 14 is supported centrally, with respect to the length anddiameter of the coil 12, in any suitable manner, not shown, and, whilepreferably grounded, may be insulated from ground or have apotentialimpressed thereon.

The shield 15, su ported in the chamber portion 4, is prefera ly ofmetal.

The condenser plates 18 are disposed with respect to the beam 30 in suchmanner that, when the beam 30 tends to move therebetween, in a planesubstantially parallel thereto, it is also deflected by a voltage fromthe circuit 27 at ri ht angles to that plane and proportionaIto thesecond magnitude quantity measured, such as time, amperes or otherquantity.

In operation, under normal condltions in the line 20, the beam 30projects in a direct line from the cathode 7, through the anode opening29, through a position between the condenser plates 10 and through theslot 35, to the target 14 by which it is absorbed. The target, beingover the opening 16 in the shield 15, protects the sensitized element 3against fo ing by diffusion rays from the beam 30.

5hen a voltage surge occurs on the line 20, by an inductive lightningcharge or other cause, the proportionately increased voltage between thecondenser plates 10 causes a deflection of the beam b a space effect orelectrostatic field action between the plates 10.

Such deflection is illustrated, in Fig. 1, whereby the beam 30 extends,between a position adjacent to the center of the space between theplates 10 and through a position adjacent to t e left end of the slot35, to a left-sidecenter position in the coil 12.

During transit through the coil 12, the beam 30 is twisted, as ishereinafter more fully explained in connection with Figs. 2 and 3, sothat it emerges from the lower slot 36, at an angle to its line ofentry, to the upper slot 35. Irrespective of the degree or amplitude ofdeflection suflicient to cause the beam to bypass the target 14, thebeam is always focused or directed through the opening 16 in the shield15 and, if the condenser plates 18 are deenergized, oscillates back andforth between these plates in a plane substantially parallel thereto torecorda line XX on the record element or plate 3. The line X-X, undersuch conditions, is an indication of the maximum deflection of one ormore deflections of the beam.

However, to obtain a time-voltage wave or curve record 38 on the element3, the condenser plates 18, are energized and disposed to deflect thebeam at right angles to its original deflection along the line X-X inthe direction of a line YY of the element, the resultant movement of thebeam causing the curve 38.

In similar oscillographs heretofore employed, the condenser plates whichare displaced by the coil 12 hereof, were necessarily of flat-planeshape and in parallel-plane relation, the size of such plates and thediameter of the intermediate chamber portion thus de pending on eachother. In other words. with the chamber portion 4 of the diameter shownherein, the condenser plates which might replace the coil 12, fordeflecting purpose only, would limit the amplitude of beam deflectionconsiderably, as compared with the amplitude permitted by my device. Inthis device, the amplitude of beam deflection is limited only by thediameter of the chamber 4 and not by condenser plates that could beplaced thereln.

By reason of this increased deflection, the blind spot caused on thecurve 38 when the beam passes laterally over the target 14 becomes asmaller proportion of the curve. Further, by the construction shown,both the target 14 and the opening 16 may be smaller.

Referring to Figs. 2 and 3, in which corresponding parts are designatedby corresponding reference characters, cylinders A and B are illustratedwhich, however, are not actually solids or structural elements in thedevice but are only outlines of cylindrical spaces about which the beam30 is lielically twisted by a space or magnetic-field effect thereon ofthe coil 12. I

When the beam 30 is deflected to the left, as viewed in Fig. 3, by theeffect of the plates 10,

it pivots about a center point between the plates 10 and along thestraight-line slot 35 to a point M adjacent to the upper-end perimeterof the cylinder A.

The plates 32 and 33 are of magnetic material to cause a straight-linemagnetic field therebetween that shall be parallel to the cylinders Aand B.

The beam 30, entering this straight-line field at the point M at anangle to the field lines, is reacted upon b these lines to cause thebeam to twist helically about the cylinder A and to approach the lowerslot 36 from a point N.

As viewed in Fig. 2, the point N is about 200 about the cylinder A fromthe point M.

As shown more clearly in Fig. 2, the beam 30 is tangent to the cylinderA at both its approaching position M and at its departing position Nrelative thereto, thereby causing the beam, after deflection from itscentral origin or zero path between the plates 10, to return to a pointon this path at the aperture 16 in the shield 15.

The point between the plates 10 and the point at the aperture 16 are euidistant from the center of the coil 12 at w ich the target 14 isdisposed.

Thus, aside from the helical or twisting effeet on the beam, the coil 12acts as a lens to return the beam to its neutral or origin line.

As the beam 30 above the plate 32 swings back toward the central axis ofthe plate along the slot 35, the cylinder A progressively decreases indiameter until, at said axis, the cylinder disappears entirely orbecomes merged as a straight line coincident with the then straight-linebeam which hits the target 14. During this movement, and so lon as thecylinder A retains its identity as suc 1, the beam 30 is helicallytwisted about the cylinder but finally resolves itself into a straightline at the central axis or origin line of the beam.

Continued deflection of the beam to the right of center above the plate32 begins the creation of the space cylinder B which graduually growslarger until it reaches the maximum diameter illustrated and about whichthe beam is similarly helically twisted and in the same direction tothat in which it is twisted about the cylinder A.

Irrespective of the helical twisting of the beam in the space betweenthe plates 32 and 33, it pivots about the central point between theplates 10 in the plane of the slot 35 and about a point in the aperture16 in the plane of the slot 36. Below the shield 15, the beam is againdeflected by the space eflect provided by the plates 18.

Referring to Fig. 4, the beam 30 is shown in the position it occupies inFig. 1 and in the position it occupies at the left in Fig. 3. Lines 40diagrammatically outline diffusion rays from the beam 30.

While the beam gradually increases its diffusion from the anode opening29, it is still appreciably concentrated at the point between t e plates10 and, as it passes through the concentration coil 12, it is againconcentrated at the point 16 to a degree substantially equal to itsconcentration at the point between the plates 10.

This action serves to 've a sharp record or line 38 on the sensitizeelement 3.

Devices heretofore employed have utilized condenser plates similar tothe plates 10 and 18 but have also used another set of plates.therebetween to cause the deflection caused by the coil 12 herein andhave required a further element or coil for concentrating the beam.

By my invention, the functions of the intermediate set of plates andcoil or coils, which have been used for concentration purposes alone,have been combined in one unit or entity, namely, the coil 12 and itsappurtenant parts, with a resultant saving of space, reduction in thenumber of parts, economy of manufacture and other advantages.

While I have shown and described a particular form of my invention, chanes may be made therein without departing rom the spirit and scopethereof, as set forth in the appended claims.

I claim as my invention:

1. In combination, means for projecting a permeable trace through spacefor producing a remote effect, and means including a unitary deviceproviding a space effect afl'ecting the trace to concentrate the sameand to direct the trace in accordance with predetermined conditions.

2. In combination, in electrical apparatus, means for eflecting anelectrical space discharge, and means including a unitary deviceproviding electrical space eflect aflecting the discharge to concentratethe same and to direct the discharge in accordance with predeterminedconditions.

3. In combination, in electrical apparatus, means for maintaining anelectrical discharge beam, means for preventing access of the beam to apredetermined position, and means for rendering said preventing meansinoperative to prevent access of the beam to said osition including aunitary device for directing and concentrating the beam.

4. In combination, in electrical apparatus, means for maintaining anelectrical discharge beam, means for preventing access of the beam to apredetermined position, and means for rendering said preventing meansinoperative to prevent access of the beam to said position includingmeans for deflecting the cam and a unitary device for re-directing andconcentrating the beam.

5. In combination, in electrical apparatus, means for maintaining anelectrical discharge beam, means including a unitary device forconcentrating the beam and deflect- Ill) ing it in accordance withpredetermined conditlons, and means for re-directing the beam. 6. Incombination, in electrical a aratus, means for maintaining an electricalischarge beam, means for deflecting the beam, means including a unitarydevice for concentratin the deflected beam and re-directin it, an meansfor deflecting the re-directe beam.

7. Incombination, in electrical apparatus, m means for maintaining anelectrical discharge beam, means for preventing access of the beam to apredetermined position, means for rendering said preventing meansinoperative to prevent access of the beam to said 35 position includinga unitary device for directing and concentratin the beam, and

means for directing the cam after it has been directed by said device.

8. In combination, in electrical apparatus,

9 means for maintaining an electrical discharge beam, means forpreventing access of the beam to a predetermined position, means forrendering said preventing means inoperative to prevent access of thebeam to said position including means for deflecting the beam and aunitary device for re-directing and concentrating the beam, and meansfor further directing the re-directed beam.

9. In combination, in electrical apparatus, means for maintaining anelectrical discharge beam, an element having an opening through whichsaid beam may pass, and means including a unitary device forconcentrating the beam and directing it toward said openas ing.

a 10. In combination, in electrical appara tus, means for maintaining anelectrical discharge beam, an element having an opening through whichsaid beam may pass toward predetermined position, means for preventingaccess of the beam to said position, means for rendering said preventingmeans inoperative to prevent access of the beam to said positionincluding means for deflecting the beam and a unitary device forconcentrating the beam and directing it toward said opening, and meansfor directing the beam after it has passed through said opening.

11. In combination, in an oscillograph, means including spacedelectrodes energized by a source of constant voltage for maintaining anelectrical discharge beam, means for preventing access of the beam topredeter-.

mined position including a shield having an means for deflecting thebeam around said target through said opening including means energizedby a variable voltage for deflecting the beam and unitary meansenergized by a constant voltage for concentrating and redirecting thebeam.

12. In combination, in an oscillograph, means including spacedelectrodes energized by a source of constant voltage for maintaining anelectrical discharge beam, means for opening and a target over saidopening, andpreventing access of the beam to predetermined positionincluding a shield having an openin and a target over said opening meansor deflecting the beam around said target through said 0 ening includingmeans energized by a varia le voltage for deflecting the beam andunitary means energized by a constant voltage for concentrating andredirecting the beam, and means energized by another voltage for furtherdeflecting the beani'in accordance with a time constant.

13. In an oscillograph, means for positioning a sensitized record sheet,means including spaced electrodes energized by a source of constantvoltage for maintaining an electrical discharge beam, a shield having anopening, a target on a line between said opening and the original zeroline of the beam, means for deflecting the beam around said target inaccordance with a quantity to be measured, a single coil forconcentrating and redirecting the deflected beam through said openingonto said record sheet, and means for deflecting the beam after it hasbeen passed through said opening.

14. In a cathode-beam oscillograph, a cathode, an apertured anodethrough which a cathode beam is projected, means for deflecting the beamas it comes from the anode, means including a single coil forconcentrating and redirecting the deflected beam, a target in a. spacesurrounded by said coil, an apertured shield toward the aperture ofwhich the beam is directed by said coil, means for deflecting the beamafter it passes through said shield, and means for recording movement ofthe beam.

15. In a. cathode-beam oscillograph, a

fluid-tight vessel including a base-end recording-chamber portion, anintermediate beamcontrol chamber portion and a top-end electrode chamberportion, a cathode in the electrode-chamber adjacent the top-endthereof, an anode disposed, and having an opening communicating, betweenthe electrode-chamber and the intermediate chamber through which acathode beam passes, condenser elements in the intermediate chamberbeneath the anode for deflecting the beam, a single coil beneath thecondenser elements for concentrating and redirecting the beam, a targetin the intermediate chamber surrounded by the coil, a shield in theintermediate chamber below the coil having an aperture toward which thebeam is directed, and condenser elements in the intermediate chamberbelow the coil for deflecting the beam at right angles to itsdeflection, caused by said first condenser elements and the coil, afterit passes through the shield.

16. In a cathode-beam oscillograph, a fluid-tight vessel includin abase-end recording-chamber portion, an intermediate beamcontrol chamberportion and a top-end electrode chamber portion, a cathode n theelectrode-chamber adjacent the top-end thereof, an anode disposed, andhaving an opening communicating, between the electrode chamber and theintermediate chamber through which a cathode beam passes, condenserelements in the intermediate chamber beneath the anode for deflectingthe beams, a single coil surrounding the intermediate chamber portionbeneath the condenser elements for concentrating and redirecting thebeam, slotted plates in the intermediate chamber adjacent to the ends ofthe coil, a target in the intermediate chamber surrounded by the coilbetween said plates, a shield in the intermediate chamber below the coilhaving an aperture through which the beam is directed, and condenserelements in the intermediate chamber below the coil for deflecting thebeam at right angles to its deflection, caused by said first condenserelements and the coil, after it passes through the shield.

17. In electrical apparatus, means for generating anelectrical-discharge beam, means for preventing access of said beam to apredetermined position, and means for rendering said preventing meansinoperative to prevent access of the beam to said position, including apair of deflecting plates and a concentrating coil.

18. In electrical ap aratus, means for generating an electricalischargebeam, a target positioned below said means for preventing access of saidbeam to a predetermined position, and means for rendering said targetino erative to prevent access of the beam to said position, including apair of deflecting plates located between said first-named means andsaid target, and a concentrating coil positioned below said deflectingplates.

In testimony whereof, I have hereunto subscribed my name this 17th dayof June, 1929.

OTTO ACKERMANN.

